1. Field of the Invention
This invention relates to novel cyclic organic silicon compounds having a Si--Si bond to which an aryl group such as a phenyl, tolyl or naphthyl group is attached and a method for preparing the same.
2. Prior Art
For the purpose of using siloxanes as resists, several attempts were made in the prior art to increase the reactivity of siloxanes by incorporating a Si--Si bond therein as reported by Ishikawa, Journal of Polymer Science, 21, p657 (1983). It was difficult to incorporate a controlled amount of Si--Si bond into siloxanes having an increased number of recurring Si--O--Si linkages.
In the silicone industry, it is practiced to produce high molecular weight polysiloxanes through ring-opening polymerization of cyclic siloxanes such as octamethylcyclotetrasiloxane in the presence of an acid or alkali catalyst. If a method capable of producing a siloxane having a Si--Si bond in high yields and high purity is available, then it is possible to incorporate a controlled amount of Si--Si bond into polysiloxanes. However, the prior art methods failed to produce a siloxane having a Si--Si bond in a practically acceptable manner.
Known synthetic methods of siloxanes having a Si--Si bond are by condensation of silanols with chlorosilanes as reported by Wu, Journal Chemical Engineering Data, 18 (3), p350 (1973), by oxidation of polysilanes as reported by West, Organometallics, 1 (12), p1801 (1983), and by introducing silylene into siloxanes as reported by Weber, Journal of Organometallic Chemistry, 133 (2), C17 (1977). These methods are not commercially feasible because of restricted supply of starting reactants and low product yields.